Benefit Plans (Components of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Benefits [Member]
Net periodic benefit cost:
Service cost	$ 8.5	$ 8.9	$ 8.6
Interest cost	15.5	16.0	15.7
Expected return on assets	(16.4)	(16.0)	(14.7)
Amortization of prior service (credit) cost	(1.4)	(1.5)	(1.1)
Amortization of transition obligation	0.1	0.1	0.1
Amortization of actuarial loss (gain)	8.5	6.0	5.6
Curtailment	0	(0.2)	0
Settlement effects	0	0.8	0
Net periodic benefit cost	14.8	14.1	14.2
Other changes in plan assets and benefit obligations recognized in other comprehensive income, pre-tax:
Net loss (gain) arising during period	17.3	46.7	9.1
Prior service credit arising during period	0	0	(5.2)
Amortization of prior service credit (cost)	1.4	1.5	1.1
Amortization of transition obligation	(0.1)	(0.1)	(0.1)
Amortization of actuarial (loss) gain	(8.5)	(6.0)	(5.6)
Curtailment	0	0.2	0
Settlement effects	0	(0.8)	0
Total recognized in other comprehensive income	10.1	41.5	(0.7)
Total recognized in net periodic benefit cost and other comprehensive income	24.9	55.6	13.5
U.S. Pension Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	12.0	11.4	11.7
International Pension Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	2.8	2.7	2.5
Other Retirement Benefits [Member]
Net periodic benefit cost:
Service cost	1.3	1.2	1.1
Interest cost	1.0	1.0	0.8
Expected return on assets	0	0	0
Amortization of prior service (credit) cost	0.1	0.1	0.1
Amortization of transition obligation	0	0	0
Amortization of actuarial loss (gain)	0	0	(0.1)
Curtailment	0	0	0
Settlement effects	0	0	0
Net periodic benefit cost	2.4	2.3	1.9
Other changes in plan assets and benefit obligations recognized in other comprehensive income, pre-tax:
Net loss (gain) arising during period	2.1	1.3	(1.5)
Prior service credit arising during period	0	0	0
Amortization of prior service credit (cost)	(0.1)	(0.1)	(0.1)
Amortization of transition obligation	0	0	0
Amortization of actuarial (loss) gain	0	0	0.1
Curtailment	0	0.4	0
Settlement effects	0	0	0
Total recognized in other comprehensive income	2.0	1.6	(1.5)
Total recognized in net periodic benefit cost and other comprehensive income	4.4	3.9	0.4
U.S. Defined Benefit Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	2.4	2.3	1.9
International Defined Benefit Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	$ 0	$ 0	$ 0